Over time, road film builds up on windshield wiper blades, reducing their effectiveness, so wiper blades should be washed regularly in a mild cleaning solution.
Checking the condition of the windshield wipers
Windshield wiper assemblies should be inspected regularly. If inspection reveals hardened or cracked rubber on the blades, replace the blades. If inspection reveals nothing unusual, wet the windshield, turn on the wipers, let them run for a while, and turn them off. Uneven marks from the blades on the glass or streaks on clean glass indicate that the blades should be replaced.
If the wipers do not clean the windshield well enough, the following reasons may be the cause.
When your car goes through an automatic car wash, wax particles get on your windshield. These particles can be removed by adding a wax-dissolving detergent to your windshield washer fluid.
Filling the reservoir with a glass cleaner with wax-dissolving properties can significantly improve the performance of the windshield wipers. Grease-dissolving cleaners are not able to completely clean the glass.
Damage to the brushes can also be the reason for poor glass cleaning; the brushes should be replaced.
During operation of the windscreen wiper mechanism, the mounting nuts may become loose, so they should be checked and, if necessary, tightened each time the wipers are checked (refer to Chapter Body for more detailed information on the operation of the windshield wiper mechanism).
(This article was copied from an online resource: audimanual)